Why Diets Don’t Work
In a world that celebrates rapid transformations and quick-fix solutions, it’s no surprise that diet culture continues to thrive. Many people embark on diets with the hope of achieving long-term weight loss and improved health. However, research and lived experiences tell a different story — one that shows diets rarely result in sustained weight loss and can often cause more harm than good.
The diet industry is built on a revolving door of weight-loss promises. From low-carb plans to detox cleanses to intermittent fasting, the market is flooded with programs that claim to help people achieve long-term weight loss. But if these diets worked, why do so many people find themselves yo-yo dieting or constantly searching for the next solution?
The truth is that the diet industry thrives on repeat customers. The majority of people who lose weight on a diet regain it within a few years — often gaining back more than they initially lost. This pattern of weight loss and regain, also known as weight cycling, is not only ineffective but also harmful to physical and mental health.
But why don’t diets work?
Diets fail to produce lasting weight loss for several reasons, including biological, psychological, and behavioral factors, including:
1. Diets Trigger Your Body’s Survival Mechanisms
When you go on a calorie-restrictive diet, your body perceives it as a threat to survival. The human body is designed to protect against starvation, so when you drastically reduce your calorie intake, your body responds by slowing down your metabolism to conserve energy. This is known as adaptive thermogenesis.
Over time, this slower metabolism means that your body uses fewer calories, even at rest. Additionally, your body may increase hunger hormones (like ghrelin) and decrease fullness hormones (like leptin), making you feel hungrier and more preoccupied with food.
2. Diets Are Unsustainable
Most diets involve rigid rules and restrictions that are difficult to maintain over time. Cutting out entire food groups, counting every calorie, or adhering to a strict meal plan can be exhausting and unsustainable in real life, especially when social events, stress, or life changes come into play. Even when the diet doesn’t call for such extreme restrictions,
When people inevitably “fail,” they often feel guilt and shame and wonder, “What’s wrong with me? Why don’t I have any self-control?” This can even lead to emotional eating or bingeing behaviors and the restrict-binge cycle. The all-or-nothing mindset reinforces a cycle of restricting and overeating, making long-term weight loss nearly impossible.
The diet industry thrives on people blaming themselves for failing to sustain the unsustainable.
3. Weight Loss Is Not Just About Achieving and Maintaining A Calorie Deficit
One of the biggest myths perpetuated by diet culture is that weight loss is as simple as calories in versus calories out. This is a harmful and overly simplistic narrative that ignores the complex biological, psychological, and social factors that influence body weight.
Many factors other than food intake and physical activity impact weight and one’s likelihood of losing or gaining weight including but not limited to:
• Genetics
• Hormones
• Sleep and stress levels
• Mental health/emotional wellbeing
• Access to food and healthcare
Diets don’t address these factors. Instead, they place the blame on the individual for not adhering to the plan, when in reality, biology and environment play a much bigger role than sheer effort or willpower.
4. Diets Ignore Emotional and Psychological Needs
Eating is deeply tied to emotions, culture, and connection - the family tradition of making tamales or sugar cookies around the holidays, grabbing ice cream with friends on a hot summer night, first dates at new restaurants and so on. Diets that focus solely on numbers and restrictions ignore the emotional and psychological aspects of eating. Diets perpetuate the myth that “food is (just) fuel” and “food is medicine.” Food is much more than just nourishment.
Sometimes we eat when we experience stress, boredom or sadness. While eating for emotional purposes isn’t inherently problematic, becoming reliant on food as a coping mechanism for uncomfortable feelings can make reading body cues like hunger and fullness confusing and ultimately build distrust with ourselves and our bodies. Diets don’t teach people how to manage emotions without turning to food.
Aside from the fact that they don’t actually work, diets can have some other pretty dark downsides:
Diets Can Lead to Disordered Eating
One of the most concerning consequences of dieting is the increased risk of disordered eating behaviors, including:
Chronic dieting
Emotional eating and/or binge eating
The restrict-binge cycle
Fear around eating certain foods
Adherence to “food rules”
Compulsive weighing or other methods of body-checking
Obsessive thoughts about food and body image
Guilt and shame around eating
These behaviors can snowball into full-blown eating disorders, which are serious mental health conditions that require specialized care.
Diets Typically Lead to Weight Cycling
Diets - in the intentional restrictive eating sense - are more likely to result in weight gain than weight loss long-term. And in the meantime, most people end up weight cycling, which has been linked to a variety of negative health outcomes, including:
Increased risk of heart disease
Higher blood pressure
Higher cholesterol levels
Mental health struggles, such as depression and anxiety
Lower self-esteem and body dissatisfaction
Ironically, the very thing people turn to for better health can make them less healthy in the long run.
The research is clear: Diets don’t result in long-term weight loss. Instead, they set people up for failure, frustration, and harm. The pursuit of weight loss through restrictive dieting is a losing battle that damages both physical and mental health.
As a dietitian, I encourage people to shift their focus away from weight and instead work on building a positive relationship with food, body image, and self-care practices.
When it comes to goal-setting, “weight loss” just isn’t a great goal - it’s not actionable. You can’t just wake up tomorrow and decide, “Today I’m going to lose ten pounds.” You can, however, decide “Today I’m going to stop and take a break for lunch,” or “This week, I’m going to eat at least one vegetable per day.” Good goals are SMART goals - Specific, Measurable, Achievable, Realistic, and Timely.
By letting go of dieting and embracing sustainable health-promoting behaviors, you can achieve better health and greater well-being.